Modular stent-graft for endovascular repair of aortic arch aneurysms and dissections

ABSTRACT

A system and method for treating and repairing complex anatomy characterized by a plurality of vessel portions oriented at various angles relative to each other. The system including a graft device that is capable of being assembled in situ and has associated therewith a method that avoids the cessation of blood flow to vital organs. A delivery catheter system and various graft supporting, mating and anchoring structures are additionally included.

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/780,943, filed Feb. 9, 2001, which is based on and claimsthe benefit of Provisional Application Ser. No. 60/187,941, filed Mar.3, 2000.

BACKGROUND OF THE INVENTION

The present invention relates to the treatment or repair of vasculatureand more particularly, to delivering a graft device within a bloodvessel to address vascular disease.

In recent years, there have been developments in the treatment or repairof the vasculature of humans or other living animals. These developmentshave been applied to various areas of vasculature to treat a number ofconditions such as vessel weakening or narrowing due to disease. Themethods developed have involved minimizing the invasive nature of repairso that patient morbidity and mortality can be reduced. The period ofrecovery has also been reduced with such advances.

Some people are prone to degeneration and dilatation of the aorta,leading to rupture and death from bleeding. A recently-developed methodof arterial reconstruction involves the attachment of a tubular conduit(graft) to the non-dilated arteries above and below the degeneratedsegment using stents; hence the name “stent-graft” for the prosthesis.The lumen of the arterial tree is used as a conduit to the aorta; hencethe name “endovascular aneurysm repair” for the procedure.

The procedure is relatively simple when the degenerated segment iswithout significant branches. The stent-graft needs only one lumen withan orifice at each end. But the procedure is much more complicated whenthe degenerated segment of the aorta contains branches, because thestent-graft also needs to branch and these branches need to be placedalong multiple lines of insertion. The most common, and simplest,example is reconstruction of the aortic bifurcation. This technicalhurdle was crossed relatively early. Yet there has been no significantprogress in the intervening years towards reconstruction of areas withmore branches, such as the suprarenal aorta, the aortic arch, or othercomplex vasculature near the kidneys or involving the hypogastric, iliacor femoral arteries. The main problem is that the branches are ofvariable size, variable orientation, and variable position. It is verydifficult to create a graft that will mimic the native anatomy, and verydifficult to place such a graft in exactly the right orientation andright position without causing ischemia of the vital organs that are fedby the aortic branches. This is especially true of the aortic arch,which has branches to the brain.

The aortic arch, for example, is affected by two degenerative processes,dissection and aneurysmal dilatation, that hitherto have been treated byopen surgical reconstruction. The open surgical operation relies uponcardiopulmonary bypass, with or without hypothermic circulatory arrest.The associated mortality, morbidity, debility, pain and expense are allhigh.

Endovascular methods of reconstruction must deal with certainchallenging anatomic features. For example, all three arteries that takeorigin from the aortic arch supply blood to the brain. Flow throughthese arteries cannot be interrupted for more than five minutes withoutrisking irreversible neurologic damage. Moreover, the distribution ofthe arteries in any one patient, and the arch arteries, in particular,is highly variable. It is, therefore, not feasible to mimic thisarrangement in every patient without very sophisticated reconstruction.Even if the graft matched the patient's anatomy precisely, it wouldstill be difficult to match the orientation and position of the branchesof the graft to the branches of the native vasculature. Additionally,the arch arteries, for example, usually arise from the ascending portionof the arch at acute angles to the downstream aorta. Trans-femoralaccess to the arch arteries necessitates a sharp change of directionwhere these arteries arise from the aorta.

However, certain anatomic features lend themselves to endovascularrepair. The aorta and in particular, the ascending aorta is long,straight and without significant branches. Further, the aorta is wideand consequently, there would be room for a main or primary graftconduit to lie alongside its branches. Also, it is relatively easy togain access to the femoral and iliac arteries.

Thoracic aneurysms typically occur in frail elderly patients, whotolerate thoracotomy and aortic cross-clamping poorly. Hence, there arehigh morbidity and mortality rates of open surgical repair for suchpatients. Endovascular exclusion can be an appealing alternative,particularly when the aneurysm involves the aortic arch and open repairwould require reconstruction of the brachiocephalic circulation underhypothermic circulatory arrest. However, to be successful, theendovascular technique must deal with a number of challenging anatomicobstacles specific to this segment of the aorta. One is the tortuosityof the aortic arch. Another is maintaining uninterrupted blood flow tothe arms and the head, while excluding the rest of the aortic arch fromthe circulation.

Endovascular techniques offer two distinct advantages over conventionalopen operative technique in the repair of aortic arch aneurysm ordissection. First, the endovascular graft is inserted through remote,easily accessible arteries outside the body cavity, whereas the openoperation often requires a combination of median sternotomy and lateralthoracotomy for insertion. Second, the endovascular graft can bedeployed without interrupting blood flow, while open repair usuallyrequires aortic cross-clamp and hypothermic circulatory arrest.

Since the challenge in endovascular repair, as in surgical repair, is tomaintain blood flow to the brain and upper extremities, variousapproaches have been contemplated. One option is to provide thestent-graft with side branches to the innominate, left carotid and leftsubclavian arteries. Another is to perform a surgical bypass from eitherthe proximal ascending aorta or from the femoral arteries. A thirdalternative that combines aspects of the other techniques can bedesirable for certain high risk patients. That is, a technique thatprovides blood flow to the innominate artery through a branch of themodular stent-graft, and blood flow to the left carotid and subclavianthrough extra-anatomic surgical bypass.

Accordingly, what is needed and heretofore unavailable is a system andmethod for treating or repairing complex vasculature while minimizingrisk and the recovery time of the patient. The present invention meetsthese and other needs.

SUMMARY OF THE INVENTION

Briefly and in general terms, the present invention is directed to adevice and method for treating or repairing diseased vasculature. Theinvention provides a minimally invasive approach to the treatment ofcomplex vasculature characterized by a first vessel in fluidcommunication with a plurality of vessel portions extending at variousangles from the first vessel. The present invention is also concernedwith treating or repairing vessels which are difficult to access andwhich supply blood to vital organs which require a continuous source ofblood and accordingly, avoids complexities associated with simultaneousinsertion and deployment of multiple components.

The present invention embodies a graft device having a superior end, aninferior end, a midsection and a plurality of apertures. Each of theapertures of the grafting device are capable of being aligned with orplaced in the relative vicinity of a vessel portion to enable anexterior component to extend from the grafting device to the vesselportion to enable an extension component to extend from the graftingdevice to the vessel portion. In one aspect, the superior and inferiorends of the graft device each include apertures and are configuredwithin a first vessel portion and each of the apertures formed in themidsection are aligned with blood vessel portions extending at an anglefrom the first vessel. Further, it is contemplated that the graft deviceincludes a main component and a plurality of extension components thatare configured to mate with the main component. Various anchoring,mating and support structures are also contemplated that facilitatesecuring the graft device within vasculature for accomplishing repairingcomplex vessel anatomy. Occlusion structures are also included that canbe used to close off one or more unused graft device apertures.

Additionally, the present invention embodies a delivery catheter systemand method that accomplishes the deployment and attachment of the graftdevice within vasculature. The delivery catheter system includesstructure for receiving the various components of the graft device ofthe present invention as well as a series of guidewires which provide apath taken by components of the delivery catheter system.

It is contemplated that a branched stent-graft of the present inventionbe constructed in-situ from multiple components, a main or primarystent-graft with multiple short branches and several branch extensions.Variations in arterial anatomy are accommodated intraoperatively throughthe independent selection of components as indicated by intraoperativemeasurements.

In one aspect, the device does not attempt to mimic native anatomy. Forexample, the widest portion of the primary stent-graft is attached(usually with a stent or an anchoring device) to the proximal aorta. Allbranches of the primary stent-graft originate at a level proximal to thebranches of the aorta. The variable gap between branches of thestent-graft and branches of the aorta is accommodated by variation inthe length of the extensions. Thus, several extensions run next to oneanother through the proximal aortic segment. This is possible becausethe central section of the primary stent-graft is sized to be muchsmaller than the native aorta in the region of the aortic branches. Thespace around the central section also allows for blood flow from thestent-graft branches to the aortic branches and continuing perfusion ofthe vital organs while extensions are added one by one. A distal aorticseal is established through a slightly wider segment. Alternatively,additional components can be added with their own branches to permitextension into other aortic branches, such as the iliac arteries.

The extensions can be fully-stented (lined from one end to the otherwith stents or some other means of support), yet flexible. As soconfigured, they maintain a stable position through a combination ofstent support and anchoring or attachment mechanisms at both ends.

The two main sites requiring this kind of treatment are the aortic archand the suprarenal aorta. The present invention also has applications inother complex anatomy including the iliac, hypogastric or femoralarteries. Although the principles are the same for such sites,differences in anatomy necessitate differences in basic technique. Forexample, in the arch, the extensions are introduced through the brancharteries, while in the suprarenal aorta the extensions are introducedthrough the stent-graft from a point of peripheral arterial access inthe upper body, usually the left upper limb.

In a preferred embodiment of the present invention, the trunk of theprimary stent-graft is bone-shaped with three segments; a narrow centralsegment and wider segments at both ends. The wider segments are largeenough to engage the aorta. Typical diameters are 3.5-4.5 cm proximallyand 2.5-3.5 cm distally. The central segment is smaller (approx. 2 cm).Three stent-graft limbs or branches arise from the transition zonebetween the proximal and middle segments. These are also small (approx.1 cm). Their origins are staggered at 1 cm intervals both down thelength of the trunk and around its circumference.

In one embodiment, there is a self-expanding anchoring device or stentin each of the five stent-graft orifices. Flexible bracing wires runalong the outer aspect of the stent-graft between all five stents, sothat each segment of the stent-graft is held to a fixed length.Guidewires run alongside the central catheter of the delivery system andthrough the stent-graft, entering through an inferior or distal orificeand exiting through the orifices of the branches to run back down theouter aspect of the stent-graft. At the base of each branch of thestent-graft there are several circumferential suture loops that formpart of a stent-graft to stent-graft mating or attachment system.

Long, flexible, narrow, fully-stented stent-graft extensions exist in arange of lengths and diameters. Each has an external grappling mechanismon the outer aspect of the graft near the proximal tip. The inner 2-3 cmof the extension is sized to match the diameter of the primarystent-graft branch (approx. 1 cm). The rest of the extension is sized tomatch the diameter of the arch artery.

The stent-graft is inserted through a flexible sheath into the arch ofthe aorta from an access point in the femoral artery. When released fromits sheath, the stent-graft expands. A catheter is advanced over one ofthe guidewires, through the trunk of the stent-graft and out of one ofthe branches. The guidewire is then withdrawn and directed into awaiting snare that was previously inserted into the aorta throughcorresponding arch artery. The distal stent-graft branch corresponds tothe left subclavian artery, the middle stent-graft branch corresponds tothe left carotid artery and the proximal stent-graft branch correspondsto the innominate (brachiocephalic) artery.

The femoro-brachial guidewires are used to insert calibrated cathetersinto the proximal aorta through the stent-graft branches. Angiographythrough the calibrated catheter allows the selection of a suitably sizedextension. Each calibrated catheter is then exchanged (over the wire)for the delivery systems of the corresponding stent-graft extension. Theextension is deployed within the stent-graft branch where it is securedby the friction generated by the outward pressure of its stents and bythe interaction of the grappling mechanism with the loops of thestent-graft branch.

In other embodiments, the application of the present invention relatesto treating complex vasculature involving the iliac, femoral, andhypogastric arteries. Various approaches are contemplated to accomplishthe in-situ assembly of components of the graft device of the presentinvention.

Other components of the present invention include employing stents witha very high expansion ratio which are flexible and have a low profile.Various methods of accomplishing secure stent-graft to stent-graftattachment are also contemplated as are various methods of providing agraft component with a desired flexibility and radial strength.

An approach involving a modular graft system and extra-anatomicalsurgical bypasses can additionally be employed to treat vasculatures. Inparticular, a large, symptomatic pseudoaneurysm of the aortic arch of ahigh risk patient can be addressed using such a combination procedure.In one aspect, a modular stent-graft is configured to provide blood flowto for example, an innominate artery and an extra-anatomic surgicalbypass is performed to provide blood flow to the left carotid andsubclavian vessels. To accomplish this, a delivery catheter loaded withat least one component of the modular stent-graft is advanced to theinterventional sets via the innominate artery.

In one particular embodiment, the modular stent-graft includes a mainbody that is bifurcated and includes a pair of unequal length anddiameter legs. Stents are positioned along the main body for support andanchoring within vasculature. Other configurations of the main body arealso contemplated.

These and other objects and advantages of the invention will becomeapparent from the following more detailed description, when taken inconjunction with the accompanying drawings of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, depicting one component of a graft deviceof the present invention;

FIG. 2 is a perspective view, depicting one embodiment of an anchoringdevice of the present invention;

FIG. 3 is a perspective view, depicting a second embodiment of ananchoring device of the present invention;

FIG. 4 is a perspective view, depicting a support structure of thepresent invention;

FIG. 5 is a cross-sectional view, depicting one embodiment of matingstructures of a component of a graft device of the present invention;

FIG. 6 is a cross-sectional view, depicting a second embodiment ofmating structure of a component of a graft device of the presentinvention;

FIG. 7 is a cross-sectional view, depicting a third embodiment of matingstructure of a component of a graft device of the present invention;

FIG. 8 is a perspective view, depicting one embodiment of grappling orcorresponding mating structure attached to a component of the graftdevice of the present invention;

FIG. 9 is a partial cross-sectional view, depicting a first stage ofdeployment of a graft device of the present invention withinvasculature;

FIG. 10 is a partial cross-sectional view, depicting a first stage ofdeployment of a graft device of the present invention withinvasculature;

FIG. 11 is a partial cross-sectional view, depicting a third stage ofdeployment of a graft device of the present invention withinvasculature;

FIG. 12 is a partial cross-sectional view, depicting a fourth stage ofdeployment of a graft device of the present invention withinvasculature;

FIG. 13 is a partial cross-sectional view, depicting an alternativeembodiment of one component of a graft device of the present invention;

FIG. 14 depicts a first stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 15 depicts a second stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 16 depicts a third stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 17 depicts a fourth stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 18 depicts a fifth stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 19 depicts a sixth stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 20 depicts a seventh stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 21 depicts a eighth stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 22 depicts a ninth stage in deployment of another embodiment of acomponent of the graft device of the present invention;

FIG. 23 depicts a graft device of the present invention in combinationwith an occlusion device;

FIG. 24 is a perspective view, depicting another alternate embodiment ofa graft device of the present invention;

FIG. 25 is a perspective view, depicting a further alternate embodimentof a graft device of the present invention;

FIG. 26 is a perspective view, depicting another further alternateembodiment of a graft device of the present invention;

FIG. 27 is a partial cross-sectional view, depicting a first step in acombined approach to treating vasculature;

FIG. 28 is a partial cross-sectional view, depicting a second step in acombined approach to treating vasculature;

FIG. 29 is a partial cross-sectional view, depicting a third step in acombined approach to treating vasculature;

FIG. 30 is a partial cross-sectional view, depicting a fourth step in acombined approach to treating vasculature;

FIG. 31 is a partial cross-sectional view, depicting a fifth step in acombined approach to treating vasculature;

FIG. 32 is a partial cross-sectional view, depicting a sixth step in acombined approach to treating vasculature;

FIG. 33 is a partial cross-sectional view, depicting a seventh step in acombined approach to treating vasculature;

FIG. 34 is a partial cross-sectional view, depicting a eighth step in acombined approach to treating vasculature; and

FIG. 35 is a partial cross-sectional view, depicting a ninth step in acombined approach to treating vasculature.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the drawings, which are included for purposes ofillustration and not by way of limitation, the present invention isembodied in a system and method for treating or repairing complexvasculature that feeds vital body organs. In one aspect of theinvention, disease affecting the vasculature proximal the aortic arch isaddressed while in other aspects, disease affecting complex vasculatureincluding the thoracic, renal, iliac, femoral or hypogastric arteries isaddressed. It is contemplated that an approach involving an in-situassembly of a modular graft device be employed to treat or repair suchvasculature. Accordingly, various anchoring, mating, and supportstructures are contemplated as well as a delivery catheter system foraccomplishing the deployment of the same. Further, the present inventionprovides a minimally invasive technique for addressing disease byavoiding conventional invasive surgery that has heretofore been requiredto repair highly complex portions of vasculature.

Referring now to FIG. 1, there is shown one application of the presentinvention. As shown in FIG. 1, the present invention includes a first ormain graft component 50. The main graft component 50 embodies agenerally tubular shape involving a superior end portion 52, an inferiorend portion 54, and a midsection 56. Each of the superior 52 andinferior 54 end portions includes openings or apertures 58, 60.Additionally, the main graft component 50 includes a plurality of limbs62, 64, 66 extending in an inferior direction (though they can extend invarious and varied other directions) from a superior end portion of themain component 50. Each of the limbs 62, 64, 66 include openings orapertures 68, 70, 72 at terminal ends of the limbs 62, 64, 66. Althoughthe figures depict three such limbs, fewer or more limbs may be providedfor a particular purpose. The limbs can be different lengths and can belocated at different axial and circumferential locations along the maingraft.

To minimize the outer profile of the main component 50 and to otherwiseprovide a space for the limbs 62, 64, 66 and other components of thepresent invention, the midsection 56 of the main component 50 isnarrowed with respect to the superior 52 and inferior 54 ends. That is,the midsection 56 has a circumference or radial dimension less than thatof the superior 52 and inferior 54 ends, whereas the superior 52 andinferior 54 ends can have the same or different circumferences or radialdimensions. A transition section 74 is included medial each of thesuperior 52 and inferior 54 end portions whereat the circumference ofthe graft device narrows to that of the midsection 56. The circumferenceor radial dimension of the limbs 62, 64, 66 is generally less than thatof the midsection section 56 and the limbs 62, 64, 66 can have equal orvaried circumferences.

The main component can be fabricated by any convention means whether itbe assembling separate pieces of graft material into a desiredconfiguration or employing various weaving techniques to thereby have aone piece design. In one preferred approach of manufacture, severaltubular pieces of standard vascular material can be attached to eachother using suture. Further, the trunk (superior, inferior, andmidsection portions) and limbs can embody woven polyester or PTFE foldsor areas of double layers of material can be added as required to attachanchoring, grappling or support structures to the graft component.

In the present invention, it is contemplated that the superior endportion 52 be configured with an anchoring device 76 that operates toattach the main component 50 within vasculature. The anchoring device 76can be placed or attached to an interior or an exterior of the maincomponent 50 and can assume various forms. Additionally, the maincomponent 50 can include support structures extending the entire lengthor a portion of the length of the main component 50 and variousstructures for mating with other graft components. The anchoring devicecan be within the length of the main graft or extend beyond the end ofthe graft as shown.

With reference to FIGS. 2 and 3, there is shown two forms of anchoringdevices which may be used, although other forms can be employed asnecessary. As shown in FIG. 2, a generally sinusoidal anchoring device80 including a plurality of alternating apices 82 configured withtorsion springs 84 and wall engaging members 86 attached to members 88connecting the apices 82 is one acceptable device for attaching thegraft component 50 within vasculature. Another acceptable anchoringdevice 90 (FIG. 3) is embodied in a flat wire frame 92 that hasalternating apices 94, curved members 96 connecting the apices 94 andwall engaging members 98 extending from selected apices 94. Each ofthese devices 80, 90 can be attached to any portion of the maincomponent 50 or other components which mate with the main component 50,by sewing or gluing or spot deformation welding, for the purpose ofanchoring such graft components to vasculature. Further, these devices80, 90 can be self-expanding or manufactured so that a radial force isrequired for expansion.

Moreover, with reference to FIG. 4, the main component 50 or othercomponents mating therewith may include support structure 100 configuredabout an exterior circumference or internal bore of the particularcomponent. One such support structure 100 may include a flat wireframework defining a plurality of connected and embedded, generallyalmond-shaped apertures 102. The members 104 defining the almond-shapedapertures 102 are curved in a manner to optimize radial expansion andstrength while providing a small profile when compressed. The ends 104,106 of the support structures 100 is defined by a plurality of apices108 of the almond-shaped apertures 102 and members 104 defininghalf-almond shaped gaps 110. Such a support structure 100 can bemanufactured to be long enough to support the entire length of a graftcomponent or a plurality of support structures having a desired lengthcan be placed in series along the particular graft component to providethe longitudinal and axial flexibility desired for a particularapplication. Generally, it is contemplated that the support structure100 is self-expanding; however, it may be desired that for certainapplications, a balloon catheter can be utilized to expand the supportstructure 100.

It is also contemplated that support structures can embody a modifiedform of the device shown in FIGS. 2 and 3. That is, acceptable supportstructures can embody the sinusoidal frame without the wall engagingmembers 86 of the anchoring device 80 shown in FIG. 2 or the flat wireframe 92, without wall engaging members 98, of the anchoring device 90shown in FIG. 3. In both cases, a series of such devices can be placedalong a selected length of a particular graft component.

Additionally, in other embodiments a bracing device (not shown) in theform of an elongate wire or equivalent structure can be configuredbetween anchoring devices or other support structures attached to agraft component. The bracing device is intended to provide theparticular graft component with longitudinal stiffness and pushability

Although the anchoring, support, and bracing wire structures can be madefrom radiopaque material, radiopaque markers can also be added tocomponents of the graft device of the present invention. Such markerscan be sewn into material used to manufacture the particular graftcomponent. The radiopaque markers or other radiopaque structures areused during the advancement and deployment of a graft component withindiseased vasculature. High resolution imaging is employed to view such aprocedure. Fluoroscopy and other remote imaging techniques are alsocontemplated to accomplish the viewing of the radiopaque structuresduring an implant procedure.

Turning now to FIGS. 5-7, there is shown various mating structures formating or connecting one portion of one graft component to another graftcomponent. With reference to FIG. 5, a first embodiment of matingstructure 120 includes a suture 122 that is configured about an interiorcircumference of a graft component 123. The suture 122 is configuredinto a plurality of loops 124 by connecting multiple point locationsthereof to the graft component 123 by any suitable means such as ringsor other suture material 126. Although the suture 122 is shown routedabout an interior of the graft component 123, it can likewise beattached to an exterior thereof. In either case, the mating structure120 is adapted to engage a framework extending radially outwardly fromanother graft component.

A similar approach is shown in FIGS. 6 and 7. The mating structure 130depicted in FIG. 6 embodies a circumferential fold 132 formed in a graftcomponent 133, the fold 132 being held in place with clips or sutures134 or any other equivalent means.

As shown in FIG. 7, the mating structure 140 can be defined by aframework 142 having opposing or alternating apices 144 and can beaffixed to an interior (or exterior, as needed) circumference of a graftcomponent 145 by sutures or equivalent structure 146. In one aspect, theapices 144 at a superior end 148 of the support structures 140 areintended to extend slightly radially inwardly so that a suitableengaging surface is provided. It is to be recognized that various formsof framework can be employed as such a mating structure provided thedesired mating function is accomplished.

Moreover, the mating of two components of a modular graft can beaccomplished through the frictional engagement of an outer circumferenceof one component with an inner circumference of another component. Sucha frictional engagement can rely on surface irregularities or other moredefined projections or can employ adhesives. It is also contemplatedthat structures such as that depicted in FIGS. 2 and 3 can be used tojoin two components. The wall engaging members 86, 98 of thosestructures 80, 90 are contemplated to lock the components together bypenetrating the walls defining the components being joined. Theexpansion of the structures 80, 90 also ad in maintaining a sealedconnection.

As shown in FIG. 8, a typical extension component 150 can embody agenerally tubular shape. However, it is also contemplated that a limbcomponent can also be bifurcated or trifurcated. The extensioncomponents can be made of any suitable conventional material. In onepreferred embodiment, the extension components are made of PRFE.

A mating end 152 of a typical extension component is provided with someform of projection or grappling mechanism for engaging the correspondingmating structure of another graft component. In FIG. 8, there is shownone embodiment of an acceptable grappling or mating structure 154,although various other forms are possible. The mating structure 154 caninclude a self-expanding or balloon expandable framework defined byopposing apices 156 and can be attached to a graft component 150 byconventional methods such as suturing. One end 158 of the matingstructure 154 embodies apices 156 which project radially outwardly fromand around the outer circumference of the graft component 150. Suchstructure can alternatively be placed about an interior circumferencefor a particular application. Being so configured, the extensioncomponent can be placed within or about another graft component so thatthe corresponding mating structures are placed beyond each other andthen the components can be moved relative to each other so that theyoverlap and sealingly engage.

One application of the present invention is to treat or repair diseasedvasculature involving the aortic arch (See FIGS. 9-12). Since suchvasculature varies from patient to patient, an attempt to mimic thenature vessel anatomy is not made. Rather, the graft device of thepresent invention is assembled in-situ in a manner to maintain bloodflow through the various branches of the anatomy by extending graftconduits from a main component to the necessary locations. Blood therebyflows through the graft device rather than through the diseasedvasculature.

For example, the widest or superior portion 52 of the generallybone-shaped main graft or primary stent-graft component 50 is attachedto the proximal aorta 162 (FIG. 9). Typically, the main graft component50 has a diameter of 3.5-4.5 cm at the superior end 52, 2.5-3.5 cm atthe inferior portion 54 and about 2 cm at the midsection 56. Allbranches or limbs 62, 64, 66 of the main component 50 have a diameter ofabout 1 cm and originate at a point proximal (closer to the heart) tothe branches 164, 166, 168 of the aorta 162 to be treated. The origin ofthe limbs 62, 64, 66 can be staggered at about a 1 cm interval as shownin FIG. 9 or can originate generally at the same longitudinal location.Where the objective is to treat the aortic arch, for example, therelatively narrow midsection 56 provides a space for the various limbs62, 64, 66 as well as a space for blood flow during the implantprocedure, thereby providing continuous perfusion of blood to vitalorgans and the innominate (brachiocephalic) artery 164, the left carotidartery 166 and the subclavian artery 168.

In order to deliver the main component 50 within the aortic arch 162, aconventional delivery catheter (not shown) can be employed. Such adelivery catheter will embody a device or structure for accomplishingrelative movement between the main component and the delivery catheterand deployment of the main component from the catheter such aswithdrawing a jacket from over the device. It is also desirable to takea femoral approach and to advance the assembly over a guidewire andthrough branch arteries to reach the aortic arch.

In one preferred method, the delivery system involves a plurality ofguidewires 170, 172, 174. The catheter (not shown) retaining the maincomponent 80 is advanced over the guidewires 170, 172, 174, each ofwhich are individually routed through the interior end 54 of the maingraft component 50 and out one limb 164, 166, 168. Deployment involvesthe attachment of an anchoring device such as those shown in FIGS. 2 and3 which is affixed to the superior portion 52 of the main component 50.Thereafter, a catheter 180 is advanced over a first guidewire 170. Theguidewire 170 is then withdrawn and directed with the aid of thecatheter 180 proximate to the proximal branch artery 164.Contemporaneously, a small end hole device 190 embodying an outer sheath192 and a looped grasping terminal end 194 is placed within thepatient's body through a peripheral artery and advanced to within andbeyond the proximal branch artery 164 into the aortic arch 162.

Through relative movement between the looped terminal end 194 and thesheath 192 of the snare device 190, the looped terminal end 194 isplaced in a position to grasp the first guidewire 170. After graspingthe guidewire 170, it is used to insert a calibrated catheter 200 intothe proximal aorta 162 through the first limb 62 (See FIG. 11). Thecalibrated catheter is utilized to select a suitably sized limbextension for mating with the main component 50.

Next, the calibrated catheter 200 is exchanged (over the wire) for anextension component delivery system 210 which is adapted to retain anextension component 220 in a compressed state as well as with structuresfor accomplishing relative longitudinal movement therebetween (See FIG.12). Mating or sealing of a superior or proximal end 222 of the limbextension 220 is accomplished through the engagement between grapplingstructures such as that shown in FIG. 8 attached thereto with matingstructures such as those shown in FIGS. 5-7 which are attached to aninterior circumference of the first limb 62. The inferior or distal end224 of the extension component 220 is equipped with anchoring devicessuch as those shown in FIGS. 2

and 3. The expansion of the anchoring devices accomplishes theaffixation of the limb component 220 to the first branch artery 164.

A similar procedure is employed to attach limb extension to the second64 and third 66 limbs of the main graft component 50. Additionally,similar mating and grappling and anchoring devices are used to assemblethe graft device in-situ. As stated previously, each of the componentsof the modular graft assembly can include support structures extending aportion or entire length thereof to provide a desired flexibility andradial strength. The graft assembly can also embody the previouslydescribed bracing devices. The limb extensions themselves are designedto have a length of approximately 2-3 cm sized to match the 1 cmdiameter of the limbs of the graft, whereas the rest of the lengththereof matches the diameter of the particular branch artery.

The superior end portion 54 (See FIG. 9) of the main component 50 can beconfigured with an anchoring device 80, 90 (FIGS. 2, 3) for directattachment to the aorta. Alternatively, the inferior end portion 54 canbe equipped with mating structures 120, 130, 140 (FIGS. 5-7). Whenequipped with such mating structures 120, 130, 140, a further tubular,bifurcated or trifurcated inferior extension can be mated therewith.

When assembled at the aortic arch, the graft assembly is intended toprovide a complex conduit for blood flow. As such, disease occurring atthe arch is treated and the vasculature is repaired.

In certain situations, the ascending aorta 230 is less than 6 cm inlength thereby leaving insufficient room to both anchor the superior endportion 52 of the main component upstream of a first or proximal branch164 and provide space for the limbs 62, 64, 66 (FIG. 13). In order toavoid compromising the sealing and anchoring of the superior end portion52, the limbs can be invaginated to provide an internal docking site forlimb extensions. The mating structures can be rearranged as necessaryand the limbs can be supported or braced as necessary to accomplishsufficient sealing between graft components.

As stated, the present invention can be applied to various complexvasculatures throughout a patient's body. For example, the presentinvention can be used to treat aneurysms or stenoses found in the iliac,SMA, SFA or renal arteries. Moreover, aneurysms found in the thoracicregion of the aorta are now treatable using the repair system of thepresent invention.

If left untreated, a thoracoabdominal aortic aneurysm (TAAA) isassociated with reduced life expectancy from ruptures. Open surgicalaneurysm repair eliminates the risk of ruptures at the expense of highmortality and morbidity rates. Despite obvious advantages over thecurrent alternatives, endovascular repair of TAAA is feasible only ifflow can be maintained to all the vital branches of the proximalabdominal aorta, while redirecting flow away from the aneurysm.

The use of multi-limbed unibody grafts to repair TAAA have potentialproblems. The relative orientation of the graft limbs reflects therelative origination of the guiding catheters employed to deliver thegraft to the repair site. If the catheters twist around one another ontheir way from the femoral artery to the aorta, the branches of theunibody graft do as well. In addition, once such a graft is deployed,visceral perfusion depends on branch deployment and any delay thereofproduces ischemia.

In order to determine the feasibility of endovascular repair of TAAA, CTand calibrated catheter angiography are employed. Measurements and themapping of the target anatomy are taken and recorded. Graft componentscan then be assembled and sizes selected as necessary to be later usedin a repair procedure.

It is contemplated that TAAA repair involves prolonged periods ofmagnified high resolution imaging, during which the field ranges backand forth from the neck to the groin of the patient, while the viewranges from full left lateral to full right lateral and every angletherebetween. The patient lies in a supine position under generalendotracheal anesthesia. Arterial access is obtained through thefemoro-brachial arteries by making oblique incisions, althoughlongitudinal incisions can also be made. Heparin is given intravenouslyto maintain the activated clotting time at twice control from arterialpuncture to arterial repair. In addition, heparinized saline is infusedslowly through all individual sheaths used during the implant procedureand evoked potentials are continuously monitored. If there is anoticeable change, cerebral spinal fluid (CSF) is drained through alumbar catheter and blood pressure can be supported pharmacologically toimprove spinal perfusion.

With reference to FIGS. 14-22, various steps in treating or repairing aTAAA is described. As shown in FIG. 13, similar to the previouslydescribed graft devices, a main component 350 used in treating a TAAAembodies a superior end portion 352, an inferior end portion 354, and amidsection 356, as well as a plurality of limbs 362, 364, 365, 366. Asbefore, the main component 350 is made from conventional fabric. Anoblique anastomotic line joins the superior portion 352 to the limbs362, 364, 365, 366 and inferior end portion 354. The limbs 362, 364, 365and 366 are staggered longitudinally along the main component 350 an themidsection is tapered with respect to the superior end portion 352 toprovide space for the limb. The inferior end portion 354 can have a muchsmaller diameter to provide space for mating with limb extensions.

The diameters of the various parts of the main component depend on theanatomy of the vasculature being repaired. For instance, the overalldiameter is oversized 4-6 mm more than the thoracic aortic implantationsite whereas the limbs have diameters approximating the aortic branchesand the distal lumen is 20 mm in diameter. Moreover, the length of themain or first component 350 varies according to the extent ofinvolvement of the descending thoracic aortic 400. It is contemplatedthat there be about a 2.5 cm overlap with healthy proximal aorta and themain component 350, 2 cm overlap between side branches 402, 404, 405,406 and extension components (described below) and 1-2 cm gap betweenterminal ends of the limbs 362, 364, 365, 366 and the side branches 402,404, 405, 406. The shorter the gap the more difficult it can be toaccommodate errors in orientation. However, the longer the gap, thegreater the risk that an extension component will blow out leading tokinking or dislocation and failure. Moreover, if a limb is below acorresponding branch artery, it is very difficult to add an extensioncomponent. Accordingly, pre-sizing is of utmost concern.

An anchoring device 380, which can take various forms such as shown inFIGS. 2, 3 and 13, is affixed to a terminal end of the superior endportion 352. The main or first component 350 can be fully supported,including the limbs, with the structures previously described or manyinclude one or more discrete support structures placed therealong. Suchstructures can be placed about an outer circumference or innercircumference of the graft. The limbs can be unsupported except at theirends initially and then support structures can be placed in them later.Moreover, each of the four limbs 362, 364, 365, 366 (See FIG. 18 forlimb 365 not shown in FIG. 14) can be equipped with mating structuressuch as those shown in FIGS. 5-7. Additionally, as before, radiopaquerings or markers can be placed along the inside or outside of variouscomponents of the graft device of the present invention. These can aidin assembling as well as orientating the graft device withinvasculature.

Delivery of the main component 350 within the target site requires asheath such as a large bore 20-24 French sheath. Any conventionaldelivery catheter so equipped can be employed. Such conventionalcatheters may further include an expandable or inflatable member foropening or implanting the support and anchoring devices attached to themain component 350. The delivery catheter is additionally contemplatedto include structures or means for accomplishing relative longitudinalmovement between the main component 300 and the delivery catheter inorder to facilitate deployment and implantation. Conventional guidewiresare also contemplated for providing a path taken by any of the deliverycatheters used to deploy components of the graft device of the presentinvention.

In operation, the main component 350 is advanced to a desired levelwithin the thoracic aorta 400 and rotated to align the limbs 362, 364,365 and 366 with their corresponding branch arteries. A trans-brachialcatheter (not shown) can be used for angiographic localization of thebranch arteries. The goal is to position the terminal ends of the limbs362, 364, 365, 366, 1-2 cm above the corresponding branch artery.

With specific reference to FIGS. 15-19, there is shown a preferredprocedure for attaching or overlaying a limb extension 452 with a limb362 of the main or first component 300. As described above, the limbextensions 452 can be fully supported with the devices shown in FIGS.2-5, 15-22 about an interior or exterior of a particular limb extension452. The limb extensions are also equipped with grappling orcorresponding mating structures (See FIG. 7, for example) configured toengage structures or devices affixed to the limbs 362, 364, 365, 366.

Limb extensions 452 are contemplated to be inserted through a surgicallyexposed brachial artery, right or left, depending upon the aortic archanatomy. In theory, right-side access carries a greater risk of stroke,but it sometimes provides a less tortuous route to the descendingthoracic aorta 400. As shown in FIG. 15, a guiding catheter 500 isinserted from the brachial artery to the proximal descending thoracicaorta 400. This helps guide the catheter 500 through the aortic arch andminimizes the risk of stroke. The catheter 500 is further positionedthrough an opening 358 found in the superior end portion 352 of the maincomponent 350 and out an opening or aperture 368 formed in a terminalend of a first limb 362. At this time, a small volume of contrast can beinjected to confirm sheath positioning. Depending on the target anatomy,a small radius J-tip catheter 502 can be advanced over a previouslyplaced guidewire and utilized for directing the catheter 500 within theproper branch artery 402, the catheter providing a means of angiographyand atraumatic passage into the branch artery. Power injection of fullstrength contrast (20 ml at 20 ml/s) can be used to more clearly showthe anatomy.

The guiding catheter 500 is then replaced with a 12 French endholesheath 504 (FIG. 16). Next a delivery catheter 506 retaining a limbextension 452 (FIG. 17) is advanced within the sheath 504 and positionedwithin the target branch artery 402. The delivery catheter 506 iscontemplated to be equipped with structure or means, such as a pusherdevice to accomplish relative longitudinal movement of the catheter andlimb extensions 452 and to release the same at the target site (FIGS.18, 19). The delivery catheter 506 can further include an expandable orinflatable member 508 which is provided to facilitate implantation ofthe limb extension 452.

The foregoing is repeated until a bridge is provided from the maincomponent to each of the branch arteries (See FIG. 20). The extensions452 are placed so that there is at least a 2 cm of overlap with both thebranch artery and a particular limb of the main component. If this isnot feasible using one extension, additional extensions are added,starting distally. Another injection of contrast through the brachialsheath confirms positioning and sealing.

It is recognized that the extensions 452 as well as any other componentbeing joined, can be implanted taking either an inferior or a superiorapproach. That is, the extensions can be implanted from below the maincomponent 350 or from above as described. Additionally, extender cuffscan be employed to seal a terminal end of the extension withinvasculature. The extender cuffs can take on a myriad of forms includingan expandable or self-expanding mesh-type frame defined by crossingmembers, or may embody the attachment or anchoring devices 80, 90depicted in FIGS. 2 and 3. A simple expandable elastic tube or sleeve orequivalent structures are also suitable.

Finally, a similar procedure is used to advanced, deploy and implantinferior extension components 601, 602, 604 (FIGS. 21, 22) throughapertures 370, 371, 372 formed in the other limbs 364, 365, 366 of themain component 350. Such inferior extension components 500, 502, 604 canbe tubular or bifurcated depending on the target anatomy and can furtherinclude the supporting, anchoring, grappling and mating structurespreviously described. External structures provide necessary friction forsealing and securing a particular component, although a combination ofinternal support and anchoring devices are satisfactory as well. Shouldinferior end extensions not be required, the inferior end portions 354of the main component 300 can be configured with an anchoring device fordirect attachment to the aorta. When completely implanted at the targetsite, blood flows through the graft device of the present inventionwhich operates to exclude the diseased portion being treated.

In the event one or more of the limbs of a graft device are not needed,occlusion of that limb may be desirable. In such an instance, as shownin FIG. 23, for example, one limb can be blocked with an occlusiondevice 610. Though various forms of an occlusion device are acceptable,such as a windsock design, FIG. 23 depicts an occlusion device 610 thatembodies a closed end cuff design that is placed within a particularlimb 366. Structures causing a limb to radially contract can also beemployed and an elastic band can be used for such a purpose. Of course,any such limb or other portion of the graft device similarly occluded orcan be closed shut by suturing prior to use.

With reference to FIGS. 24 and 25, there are shown graft assembliescontemplated to be used in vasculature in an area characterized by aplurality of branching vessels. In one embodiment, the graft assembly610 includes a first end portion 612 having a main opening 614 to aninterior 616 of the graft. The graft assembly further includes a secondend portion 618 that defines a first leg 620 and a plurality ofadditional legs 622 contained in a cuff member 624. In the embodimentshown, the generally tubular first leg 620 is larger and has a largerdiameter than the additional legs 622, though the dimensions of the legscan vary for specific purposes. The cuff 624 extends beyond theadditional legs 622 and in cross-section, defines an arc, the ends ofwhich are attached to an outside surface of the first leg 620. Stents626 are positioned along the graft assembly either on the exterior orinterior thereof. Each of the legs are contemplated or configured toconnect directly to branch vessels or by way of graft extensioncomponents.

In another embodiment (FIG. 25), the graft assembly 630 has a generallytubular configuration along its length and includes a divider 632 thatdefines a pair of adjacent chambers 634, 635 within the graft 630.Housed within one chamber is a single tubular body 636 that extends fromone end to approximately half of the length of the graft 630. Threeadditional tubular members 638 are similarly housed within a secondchamber 635. Stent structures 640 are positioned along an interior orexterior of the length of the graft assembly 630 as required. As withthe previous embodiment, the various tubular members are contemplated tobe placed in fluid communication with one or more vessels branching froma main vessel.

Turning now to FIG. 26, there is shown yet another embodiment of a graftassembly 650. This graft assembly includes a main opening 652 configuredat a terminal end of a first or superior end portion 654 and abifurcated second or inferior end portion 656 that defines a pair oflegs 658, 660. A first leg 658 is shorter in length but larger indiameter than a second leg 660. Stent structures 670 are again providedsubstantively along the length of the device and can be placed upon anexterior or interior surface thereof. This bifurcated graft assembly 650has been found to be well suited for treating a diseased aortic arch andin particular, for treating a large wide-necked pseudoaneurysm of theaortic arch. One particular approach to treating this area of anatomy isprovided below.

Various approaches to repairing aneurysms occurring in or around theaortic arch are contemplated. Recent experience suggests that an aorticstent-graft can occlude the origin of the left subclavian artery withoutseriously compromising flow to the arm or brain, because there is a richnetwork of collaterals from branches of left carotid artery. Moreproximal placement of the stent-graft necessitates some form of bypassto the left carotid artery, usually from a branch of the innominateartery. In cases of complete arch involvement, one may need to look evenfurther afield for a source of inflow with bypass from either the aorticarch or the femoral artery. In one reported case of endovascular archreconstruction, there was an absence of a concomitant surgical bypass.In that operation, the three side branches of a unibody stent-graft werepulled into the innominate, left carotid and left subclavian arteriesusing a system of catheters.

A novel approach using modular systems of endovascular archreconstruction is contemplated. Although aspects of the approach can beused for the treatment of various other vasculature, endovascular repairof a symptomatic anastomotic pseudoaneurysm of the aortic arch using astent-graft with aortic and innominate branches is presented.

In one particular aspect, a repair prosthesis consists of at least twocomponents, a bifurcated superior or proximal component 650 (FIG. 26)and a tubular inferior or distal extension component 700 (See FIGS. 34and 35). Both are made from conventional surgical woven polyester andboth are supported by a series of stainless steel stents 670 having forexample, alternating apices. In one embodiment, it is contemplated thatno stents extend beyond the end of the fabric, either proximally ordistally. However, for particular applications, the stents can be madeto extend beyond the ends of the graft device 650. Additional tubulardistal components may be added, depending on the diameter and locationof the implantation site in the descending thoracic aorta or othervasculature.

Further, in one preferred embodiment, each proximal stent carries 12caudally directed barbs 672 (For example, See FIG. 30), which pokethrough the wall of the graft 650. All the stents are sutured inposition by 4-0 polyester suture. For treating the aortic arch, thefirst portion 654 and opening 652 are 40 mm-wide and the two limbs 658,660 are 22 mm wide and 25 mm long, and 16 mm wide and 80 mm long,respectively. Two gold markers (not shown) indicate the position andorientation of the short-wide aortic limb. Moreover, as shown below, a150 mm-long tubular distal component having a single lumen of uniformdiameter (26 mm) is used in combination with the bifurcated component.At least in one aspect, the stents are separated by 10 mm gaps forflexibility.

Essentially the same delivery system 800 (See FIGS. 30-35) can beemployed for both the bifurcated 618 and tubular 700 components, thesame consisting of a dilator assembly 810, a loading capsule or sheath820, and a central pusher (not shown). Exact sheath sizes depend on thediameter of the stent-graft. In general, the bifurcated proximalcomponent 650 is wider, requiring a 22-24 French sheath; the tubulardistal component 700 is narrower, requiring a 20-22 French sheath. Thedilator inside the sheath for the bifurcated proximal component 650 hasa short tip 812, to allow more proximal insertion without comprising theaortic valve. The dilator for the tubular distal component has a longtip 814 to track around the aortic arch.

It is contemplated that the central pusher can consist of for example, alarge-diameter balloon catheter with a side hole into the balloon lumento provide access to a Nitinol 0.018″ guidewire. The proximal end of thestent graft 650, 700 is attached to the proximal end of the centralpusher for example, by two sutures around the exposed portion of aguidewire. While the guidewire remains in place, the stent-graftattachment is secure. A stent-graft deployment is accomplished byremoving the wire to thereby release the sutures (not shown).

During loading, the stent-graft 650, 700 is compressed and pushed intoan inferior end portion of the delivery catheter 800. In practice, theoperation itself is performed under general endotracheal anesthesia.Bilateral supraclavicular incisions are used to expose the carotidarteries, the subclavian arteries, and the distal innominate artery. Theright common femoral artery is exposed through a short transverseincision at the level of the inguinal ligament. Heparin is givenrepeatedly throughout the remainder of the operation to maintain anActivated Clotting Time (ACT) of at least 300 seconds. As shown in FIG.27, a first step in treating the aortic arch 710 involves performing acarotid-carotid bypass using standard surgical technique. The conduit720, a segment of ringed 8 mm ePTFE, passes through a retropharyngealtunnel. The proximal left subclavian artery 730 (FIG. 28) is transectedand reimplanted onto the lateral surface of the left carotid artery 740below the level of the carotid-carotid bypass.

The relative sizes of the right carotid artery 750 and the deliverycatheter 800 for the bifurcated proximal component 650 are compared toassess the feasibility of transcarotid insertion. If this appearsfeasible, the right carotid artery 750 is punctured 760 below thecarotid-carotid bypass (See FIG. 29). Using the Seldinger technique, ashort sheath and catheter (not shown) are introduced into the ascendingaorta 770. A stiff guidewire 772 is inserted and the original shortsheath and catheter are exchanged for a large sheath/dilator combination800. The dilator 810 is then removed (See FIG. 30), leaving the sheath820 and guidewire 772 in place. The contained bifurcated proximalcomponent 650 of the modular graft assembly then is passed over thewire.

The device 650 is then advanced through the sheath 820 and into theascending aorta 770. Once the device 650 is in the most proximal part ofthe sheath 820, optimal position and orientation are obtained. Thedevice 650 is positioned with the markers (not shown) on the short-widelimb of the stent-graft just below the inferior/medical margin of theinnominate artery orifice. The position of the device is maintainedwhile the sheath is withdrawn, releasing the stent-graft, first into theaorta (FIG. 31) and then the second leg 660 into the innominate artery750 (FIG. 32). During the process, the catheter is manipulated tocompletely release the device from the delivery catheter 800. Thisportion of the stent-graft deployment, from fully sheathed to fullydeployed, is accomplished within a short period of adenosine-inducedasystole.

Angiograms are performed to confirm the position and patency of thebifurcated proximal component 650. If necessary, a 16×60 mm stent isinserted to eliminate kinks in the long limb 660. Assuming theappearances are satisfactory, the guidewire and sheath are completelyremoved and the transverse carotid laceration repaired. Throughout theperiod between sheath insertion and removal, flow through thecarotid-carotid bypass 720 is from left to right.

Next, the right femoral artery is punctured and access is gained to theaorta 810. A long catheter 808 is advanced, together with a guidewire810 from the femoral level to the distal aortic arch and directed intothe downstream orifice of the short aortic limb 658 of the bifurcatedproximal component 650 (FIG. 32). This catheter 808 is then exchangedfor a second sheath/dilator combination catheter 820 (FIG. 33) loadedwith the tubular distal component 700. The distal component 700 is thenpassed over the guidewire 810 and transferred into the short aortic limb658 of the bifurcated proximal component 650 (FIGS. 34 and 35). Again,stent-graft deployment is accomplished during a period ofAdenosine-induced asystole.

Thereafter, the left common carotid artery is ligated (FIG. 35) toprevent retrograde flow into the aneurysm. Completion angiograms areperformed to look for kinks or endoleaks, which should be treatedendoluminally prior to removing catheters, guidewires and sheaths. Thefemoral laceration is repaired and all three wounds are closed in theusual way.

Many of the features of the foregoing approach and system reflect thespecific demands of endovascular aneurysm repair in the aortic arch,which is large, mobile, curved, and subject to high flow rates where thesource of branches to an organ, such as the brain, have low tolerancefor ischemia. Trans-carotid insertion of the bifurcated proximalcomponent 650 has a number of beneficial effects. First, the line ofinsertion is relatively straight; therefore, the dilator 810 can beshort and blunt, the sheath 820 can be inserted almost to the aorticvalve, and rotation of the apparatus can be accomplished easily,unimpeded by the bends of the aortic arch. There is no need for theadditional support of a trans-septal guidewire. Second, the long,trailing limb 660 of the bifurcated proximal component 650 opens intothe innominate artery 750. Accordingly, there is no need for additionalside branches, which can sometimes be a potential source of difficultyand delay. The only sheath that has to traverse the transverse arch inthis procedure is relatively small and flexible with a long dilator tip.It carries the tubular distal component 700 from the femoral artery toits attachment site in the short wide limb 658 of the bifurcatedproximal component 650. The diameter of the sheath reflects the diameterof the tubular distal component, which in turn reflects the diameter ofthe short wide limb 658 and the descending thoracic aorta. As stated,the dilator tip 814 can be long, because the sheath 820 need not reachfar into the ascending aorta. Carotid-carotid and carotid-subclavianbypasses have been used before to facilitate endovascular repair of thedistal aortic arch. These extra-anatomic bypasses permit the entirebrachiocephalic circulation to be based on innominate inflow. In thistechnique, the carotid-carotid bypass also has a secondary role as aroute of perfusion to the right carotid distribution during insertion ofthe bifurcated proximal component. Without it, trans-carotid insertionwould not be safe, because the proximal right carotid is almost occludedby the large sheath.

It will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

1. A modular grafting system, comprising: a bifurcated main bodyincluding a superior end and an inferior end, the superior end beingsized to engage walls defining an aortic arch portion of vasculature,the inferior end including a first leg and a second leg, the first legbeing longer and having a smaller diameter than the second leg; and anextension component, the extension component being sized to mate withthe second leg after placement of the main body within vasculature. 2.The modular grafting system of claim 1, the main body further comprisinga plurality of stents attached thereto.
 3. The modular grafting systemof claim 2, the main body including an exterior and an interior, whereincertain of the plurality of stents are attached to the exterior of themain body.
 4. The modular grafting system of claim 2, the main bodyincluding an exterior and an interior, wherein certain of the pluralityof stents are attached to the interior of the main body.
 5. The modulargrafting system of claim 2, wherein the stents are self-expanding. 6.The modular grafting system of claim 2, at least one stent includingstructure for attaching the main body to vasculature.
 7. The modulargrafting system of claim 1, wherein the first leg is sized to extend toand engage an interior surface of a vessel branching from the aorticarch.
 8. The modular grafting system of claim 7, the first leg furtherincluding anchoring structure that attaches the first leg within thebranch vessel.
 9. The modular grafting system of claim 1, furthercomprising a delivery catheter sized to receive the main body and to beadvanced through a branch vessel extending from the aortic arch.
 10. Themodular grafting system of claim 9, the delivery catheter includingstructure for releasing the superior end and second leg of the main bodywithin the aortic arch.
 11. The modular grafting system of claim 10, thedelivery catheter being further adapted to configure the first legwithin the branch vessel.
 12. The modular grafting system of claim 9,further comprising a supplemental delivery catheter sized to receive theextension component and to be advanced upstream within an aorta to theaortic arch.
 13. The modular grafting system of claim 12, thesupplemental delivery catheter including a releasing mechanism thataccomplishes deploying the extension component at least partially withinthe second leg of the main body.
 14. The modular grafting system ofclaim 13, the extension component further comprising a first anchoringdevice and a second anchoring device, the first anchoring device beingsized to engage the second leg of the main body and the second anchoringdevice being sized to engage interior walls of the aorta.
 15. Themodular grafting system of claim 14, wherein the anchoring devices areself-expanding.
 16. A method to treat vasculature involving a modulargrafting system including a delivery catheter configured to receive amain graft body, comprising: gaining access to vasculature; advancingthe delivery catheter within vasculature and through an innominateartery branching from an aortic arch; and releasing the main graft bodyfrom the delivery catheter so that a first portion of the main graftbody resides in the innominate artery and a second portion resides inthe aortic arch.
 17. The method of claim 16, further comprisinganchoring the first portion within the innominate artery.
 18. The methodof claim 16, further comprising anchoring the second portion within theaortic arch.
 19. The method of claim 16, wherein the main graft body isbifurcated including a main opening, a first leg and a second leg,further comprising configuring the first leg in the innominate arteryand configuring the second leg in the aortic arch.
 20. The method ofclaim 16, wherein the main graft is bifurcated including a main opening,a first leg and a second leg, further comprising configuring the mainopening in the aortic arch.
 21. The method of claim 20, furthercomprising anchoring the main opening in the aortic arch.
 22. The methodof claim 16, wherein the modular grafting system further includes asupplemental delivery catheter configured to receive an extensioncomponent having a first end and a second end, further comprisingadvancing the supplemental delivery catheter upstream an aorta to theaortic arch.
 23. The method of claim 27, further comprising releasingthe extension component within the aortic arch.
 24. The method of claim23, further comprising configuring the first end of the extensioncomponent within the main graft body.
 25. The method of claim 23,further comprising anchoring the second end of the extension componentto vasculature.